THIS gentleman was elected, at the Portland meeting, last year, President of the American Association for the Advancement of Science for 1874, and will preside at the twenty-third session, to be held at Hartford, Conn., commencing August 12th. He belongs to a family that has made itself distinguished in American science, mainly in the direction of natural history and geology, his own chosen field of inquiry having been chiefly that of entomology.

John L. Le Conte was born in New York, on May 13, 1825. His father, Major John Eatton Le Conte, formerly of the U.S. Army, possessed broad culture both in science and literature, and was well known among the early botanists and zoologists of the country.

The family is descended from a Huguenot of noble birth, who emigrated to New York in consequence of the religious and political persecutions which followed the revocation of the Edict of Nantes. Major Le Conte and his brother Louis were close students and accurate observers, almost from the beginning of the century, though the extreme diffidence of the latter, added to the want of proper channels for publication, prevented him from contributing to the literature of science. Two of the sons of Louis Le Conte, John and Joseph, formerly of Georgia and South Carolina, but now of the University of California, have made many valuable additions to physics and geology.

The subject of the present sketch was inspired, at an early age, by the example and teaching of his father, with a strong passion for science. After an academic course at Mt. St. Mary's College in Maryland, where he graduated in 1842, he studied medicine at the College of Physicians and Surgeons, in New York, receiving his diploma in 1846. The intervals between the courses, and other times later in life, were occupied in extensive journeys in the United States, for the purpose of making collections in natural history, upon one branch of which, the Coleoptera of North America, he gradually concentrated his attention, while still retaining his interest and endeavoring, by books, to keep up his knowledge of collateral subjects.

In 1852 Major Le Conte and his son removed from New York to Philadelphia, which,on account of the greater activity in science then existing, was believed by them to offer, by its libraries, collections, and personal associations, better facilities for study.

The survey of the Interoceanic-Railway route across Honduras, by Mr. J, C. Trautwine, gave Dr. Le Conte an opportunity of spending a few months in the tropics in 1857; and a short memoir, on the economic geology of the State, from his pen, is contained in the final report of the survey, printed in London. Another, on the famous "Fuente de Sangre," will be found in the appendix to the second work of Hon. E. G. Squier, on Central America, solving the mystery of that singular phenomenon.

During the late civil war he entered the army medical corps as surgeon of United States volunteers, and, on the occurrence of a vacancy, was promoted to the grade of Lieutenant-Colonel and Medical Inspector U. S. A., in which capacity he served until the mustering out of the inspectors after the close of the war, in 1865.

The cessation of official duties enabled him again to resume his scientific pursuits, the results of which continue to be published in scientific magazines and transactions of learned societies.

The survey for the extension of the Kansas Pacific Railway under General W. W. Wright, in 1867, enabled him to visit a portion of Colorado and New Mexico. Some new observations on the geological structure of the regions adjacent to the route surveyed will be found in the report which he then prepared.

His contributions to the study of North American Coleoptera are very numerous; for their titles, the "Bibliographia" of Dr. Hagen, and the annual reports on the progress of entomology, must be referred to. A compendium of the arrangement adopted by him may, however, be found in the classification of the Coleoptera of North America, Smithsonian "Miscellaneous Collection," 8vo.

As an evidence of the general appreciation of his memoirs, he has been elected honorary member of many foreign and domestic scientific societies, and correspondent of a still larger number.